This is probably due to the uncompress utility being unavailable.
Make sure uncompress is available and then re-run setup.
[root@oda000 backup]# which uncompress
/usr/bin/uncompress
[root@oda000 backup]# ls -lah /usr/bin/uncompress
lrwxrwxrwx 1 root root 14 Feb 22 17:33 /usr/bin/uncompress -> /usr/bin/unzip

Note that the symlink of uncompress to unzip is directly from the OSB installation documentation. None of those files exist in /usr/tmp, but there is a similarly named .Z file there. However the file name changes, so it cannot just be renamed or manually uncompressed. I also tried extracting from the mentioned "gserver.tz" file, to no avail.

Please advise as to how to complete OSB client installation on an ODA.